Consider a composite signal with initial power 80W and has the following three components: Amplitude: 15V, Frequency: 10 Hz, Phase: 0 degree Amplitude: 8V, Frequency: 15 Hz, Phase: 45 degrees Amplitude: 2V, Frequency: (50+Y) Hz, Phase: 120 degrees where Y is the 4" digit of your student ID number. (a) Plot the composite signal in frequency domain graph. (6%) (b) Plot the composite signal in time domain graph for 1 second. (7%) [ Hint: A sine wave can be represented as f(t) = A sin(2nft + 0). You may use the online tools such as https://www.desmos.com/calculator or https://byjus.com/sinusoidal-function- calculator/ ] (c) If the signal travels through a medium with attenuateon -6dB, what is the signal power at the receiver? (6%) (d) Suppose the signal lasts for 50 seconds and is digitized by PCM using 512 levels. What is the minimum size of the resulted digital data? Express your answers in bits. (6%)